Space current device



Jan. 5,1932. l. E. MoURoMTsEl-'F SPACE CURRENT DEVICE Filed Sept. 26, 1925 WITNESSES:

Patented Jan. 5, 1932 UNETED STATESY y isasssi PATENT veiner@ ILIA n. ivrounomrsnrr, or WILKINSBURG, rnnnsvnvnnragnssrcnon mo WESTING- neuss. ELECTRIC a MANUrncTUnrNG CoMrANY, A conronATIoN or rnNNsYL- VANIA SPACE CURRENT nEvICE Application led September 26, 1,925." Serial No`.,58,814.l i

My invention relates to space-current devices and particularly to such devices which are adapted to effect translation of substantial quantities of energy at high potentials.

An object of my invention is to increase the durability of a high-capacity vacuum tube.

Another object of my invention is to reduce the effect of ionization and corona discharge upon the structure of a vacuum tube.

Another object of my invention is to provide means for strengthening'the seal construction and to reduce the breakage of the seal member in a vacuum tube.

In the construction of high-potential vacuum tubes, it is customary to employ a tubular metal anode having Vthinned edges and a glass closure sealed thereto. The glassclosure is provided with a re-entrant port-ion embodyinga press through which seal wires extend to supply and support a filamentary cathode. The same resentrant portion is used to support a grid electrode by means of a clamping band which is positioned around the re-entrant portion and which has attached to it the main supporting members of the grid structure.

Difficulty has been experienced in this conj struction because of the relatively short creepage distance across the surface of the glass from the grid band to the cathode leads. Difficulty has also been experienced with ionization of air surrounding the cathode seal wires where they pass through the seal into contact with the outside atmosphere. This ionization is caused by the high electrostatic potential between the grid band and the cathode leads, which potential is concentrated by the close spacing between the grid band and the wires.

My invention provides means both for increasing the creepagc distance and for reducing the ionization at the cathode lead wires.

Other objects and structural details of my invention will be apparent from the following description, when read in connection with the accompanying drawing, wherein:

The single figure is a View, in section, of an embodiment of my invention.

In the drawing, an anode l having thinned edges, has seale'dthereto a glass 4portion 2.

A Ire-entrant portion 3 is sealed to the vmember' 2 and has at its inner end a press 4 through which! cathode lead wires 5 and V6 are inserted. A jacket tube 7, somewhat larger than, and surrounding the reentrant portion 3, is sealed'to the re-entrant portion near the-pointof its attachment to the member2. Upon the jacket tube 7 is positioned ajgrid-supporting band S to which are suitably attached the grid-support wires 9 and l0.- Electrical connection is made! to the gridby means of a conductor 1l and a seal wire 12S which is coiled at its innerL end and flexibly attachedto the lead wire 11. l

` `My invention requires that .the gridvband 8 .be positioned even with, or above the top of the press 4f rather than below the lower edge of the press, as shown by the dotted lines 13, which indicate the customary posi-- tion of the grid-supporting band of prior constructions.

By this construction, the grid-supporting band is rmly positioned in a suitable location, whereby ample creepage distance is provided between it and the point of emergence of the cathode lead wires from the seal.

Simultaneously, the grid-support band is positioned at a point sufficiently remote from 'the point of emergence of the cathode seal wires on the air-exposed side of the seal to give a distribution of electrostatic stresses such that the potential at the surface of the Y seal wires where they emerge from the press is below the ionization potential of the air at atmospheric pressure. The lower potential avoids the production of corona discharge at the surface between the metal and glass with thereon as are indicated by the prior art or by the appended claims.

I claim as my invention:

l. A space-current device with an external anode comprising an evacuated Vvitreousinaterial container having a' re-entrant p0rtion extending upwardly therein, a press on the upper end thereof, a conductive lead extendingthrough said press, an electrode attached to said lead, a vitreous-material sleeve surrounding said re-entrant portion and attached thereto, a second electrode attached to a supporting band on said sleeve, said band being positioned above the air-exposed side of the press, and a conductive lead attached to said band.

. 2. A space-current device with an external electrode comprising an evacuated vitreousmaterial container having a re-entrant por-l tion extending upwardly therein, a press on the upper end thereof, a conductive lead extending through said press, an electrode attached to said lead, a vitreous-material sleeve surrounding said re-entrant portion and attached to and supported by the intermediate part of said re-entrant portion, a conductive supporting band on said sleeve substantially in the plane of said press and positioned above the air-exposed side of the press, and a second electrode attached to said band.

In testimony whereof, I have hereuntoV subscribed my name this 17 th day of September, 1925. ILIA E. MOUROMTSEFF. 

